Chromogens are materials which have the ability to impart a visualizable spectral characteristic to a compound, the absorption generally being in the near ultraviolet range. Fluorogens are a subclass of chromogenic materials which have the ability to impart a fluorescent or light-emitting spectral characteristic to a compound. In general, the fluorescence maxima is at a longer wavelength (less energetic) than the absorption. The ability to temporarily or permanently modify active hydrogen-containing materials (protic compounds) with a chromogenic or fluorogenic group has a multitude of applications.
For example, protic materials can be derivatized for recognition (visualization) by ultraviolet detectors in high pressure liquid chromatography, permanently bonded optical brightners for fabrics and plastics, and fluorometric biochemical assays, etc. Another conceivable application is to copolymerize these fluorescent silanes with other silanes to yield fluorescent silanes. Although monomeric silane materials theoretically represent a facile route for the derivatization of both molecular and macromolecular protic materials, such silanes with chromogenic or fluorogenic properties have generally not been available.